nope, the only person that can really fix it is mike, techknight.
He spent at least a hundred hours making his own notes and mini schematics for the portable. both 5120 / 5126.
With those notes he was able to fix everyones dead portable boards.. and yup there was many of them.
there is a thread...
https://68kmla.org/forums/index.php?/topic/22080-mr-sherlock-techknight™-51205126-mac-portable-common-issu/